Luminous electrical discharge device



une 15, 1942. .1. H. McCAULEY 2,286,634] a LUMiNOUS. ELECTRICAL DISCHARGE DEVICE Filed M8,}; 18, 1940 Patented June 16, 1942 LUMINOUS ELECTRICAL DISCHARGE DEVICE John H. McC auley, Hillside, N. J. Application May 18 1940, Serial N0. 336,035

(Cl. rill-122) 4 Claims.

This invention relates to luminous electrical discharge devices. In my prior Patents Nos. 2,132,427; 2,133,205 and 2,133,206, I have shown luminous electrical discharge tubes each consisting of a closed glass tube having spaced electrodes and containing a rare gas and a filler of insulating material which affords numerous passageways or channels through which the electrical discharge may take place. As the discharge takes one course through the gas filled passageways the temperature of the gas in that course increases, and since the resistance of the gas to the passage of the currentincreases with increased temperature, the discharge, always taking the course of leastresistance, shifts from zones where the temperature is relatively high tozones where the temperature is lower, and this shifting of the course of the discharge will go on almost continuously producing a flickering luminous efiect,

These animated tubes are mainly used for advertising purposes, to attract attention, and such a tube may be long and have filler material therein at certain portions in its length, to cause a flickering efiect only at such portions while the gas in the rest of the tube will show a steady glow; or the tube may have the filler material therein throughout the length of the tube.

I have found that the flickeringstreams of light produced by the presence of the filler in the tube are made more striking and attractive by applying to different parts of the filler diflerent kinds of fluorescent material, each adapted to produce a difierent color effect. As the electric discharge through the filled portion of the tube constantly changes its course the shifting streams of light are accompanied by constantly changing and blending of the color efiects produced by the presence of the difierent fluorescent materials on difierent parts of the filler. These effects may be obtained by the use of fillers of various kinds which afford a plurality of passageways through which the electrical luminous discharge tube containing a grooved filler of insulating material in sections which overlap, into the grooves of which coatings of difierent fluorescent materials may be applied.

Figure 2 is a section on the line 2-2 of Fi ure 1:

Figure 3- is a longitudinal central section through a discharge tube containing a grooved filler, shown in several abutting sections, into the grooves of which diiferent fluorescent materials may be applied.

In Figures 1 and 2 of the drawing a indicates a closed glass tube containing electrodes I and 2, adapted for connection to the high tension terminals of an alternating current transformer. Within the tube is a filler composed of molded insulating material of generally cylindrical form and approximately of the same diameter as the inner diameter of the tube, shown in three sections, b, b and b each section having a plurality of longitudinal grooves 4 inits periphery.

The tube contains an electrically conductive gas or vapor at sub-atmospheric pressure.' In Figure 1 the abutting ends of the filler pieces are cut diagonally, as shown at 5, and the channels in the several pieces are in alignment so that they constitute through passageways of substantially equal length, from end to end of the filler. The channels are of the same cross sectional area so that they contain columns of gas of the same length and cross section. When the current is applied the discharge passing through one channel heats the gas therein and, since the resistance of the gas increases with increase in tem- In Figure 3 I have shown a luminescent electrio discharge device comprising the closed glass tube, containing a conductive gas at sub-atmospheric pressure, and having therein the spaced electrodes 6 and I. and a filler composed of a number or relatively short pieces of molded insulating material d, d. d, d"-, fitting closely in the tube-and each having a plurality of longitudinal channels 8 in its periphery through which the electrical discharge may pass. These pieces may be arran ed closely together or spaced apart. The pieces may be placed with their channels in out the filled area.

alignment or out of alignment. When the electrodes'are connected to the high tension terminals of a transformer, the electric discharge will follow the course of least electrical resistance at any moment prevailing, whether this be a straight course or a zig zag course, through the channels of the several filler pieces, causing the appearance of constantly shifting streams of light through- In order to obtain the changing color efiects, I place in the channels of the filler pieces fluorescent material of different kinds. Thus, for instance, if the tube is filled with neon gas, a coating of zinc silicate in the grooves of one of the filler pieces will produce a yellow luminescence; calcium tungstate in the grooves of another piece will produce a violet luminescence, and calcium tungstate containing samarium will produce a red luminescence. Different fluorescent materials may be placed in the diflerent grooves of th same filler piece, or each filler piece may have only one fluorescent substance in its grooves, different from the fluorescent substances on the adjacent filler piecs. When the electric current is applied the shifting of the discharge from channel to channel, as before described, causes diiierent colors and innumerable shades of colors to show in the tube.

The fluorescent colors, of course, depend upon the kind of gaseous atmosphere in-the tube as well as upon the kind of fluorescent material on the filler. For instance, when mercury vapor is used to produce what is called blue gas, the zinc silicate fluorescent material on the filler will produce a green luminescence; calcium tungstate will show blue and cadmium silicate will show light lavender in the blue gas.

What I claim is: t

1. An animated electrical discharge device comprising a closed glass envelope containing a gaseous electrically conductive medium at sub-atmospheric pressure; spaced electrodes, a flller of in- 'sulating material within thatpart of the envelope which lies between said electrodes, said filler affording a plurality of passageways for the electrical discharge, and fluorescent material of different kinds on difierent parts of the filler adapted to produce different color effect when the electrical discharge takes place.

2. An animated electrical discharge devicecomprising a closed glass envelope containing a gaseous electrically conductive medium at sub-atmospheric pressure, spaced electrodes, a filler of insulating material within that part of the envelope which lies between said electrodes. said. filler comprising sections, each affording a plurality of passageways for the electrical discharge and each having coatings of different fluorescent materials thereon adapted to produce different color effects when the electrical discharge takes place.

3. An animated electrical discharge device comprising a closed glass envelope containing a gaseous electricallyconducti've medium at sub-atmospheric pressure, spaced electrodes, a filler of insulating material within that part of the envelope which lies between said electrodes, said filler comprising sections each aifording a plurality of passageways for the electrical discharge, each section having a coating of fluorescent material thereon, the coatings of fluorescent material on different sections being difl'erent in kind and the electrical discharge takes place.

The above-are mentioned only for the purpose of illustration, as many other colors and shades of colors may be produced with different gases and mixtures thereof and different fluorescent materials.

The insulating material is preferably white in color, so as to reflect the light. With this molded' type of filler, where a filler piece is to be coated with only one kind-of fluorescent material, and the fluorescent material is one which will not be aflected by moisture, the fluorescent material may be incorporated in the filler material while the latter is in a plasticcstate, and when the molded pieces have become dry andhardened, the fluorescent material on the surfaces of the pieces will serve the purpose of a coating.

4. An animated electrical discharge device comprising a closed glass envelope containing a gaseous electrically conductive medium at sub-atmospheric pressure, spaced electrodes, 9. filler of insulating material within that part of the envelope which lies between said electrodes, said flller composed of insulating material substantially of the same diameter as the internal diameter of the tube and having grooves in its periphery for the passage of the electrical discharge, and having fluorescent material of different kinds in said grooves adapted to produce difierent, color effects when the electrical discharge takes place.

JOHN H. MCCAULEY. 

